Do a voltage mod to your 6800 to clock up the memory clock speed!
For VDDR mod for the 6800 Ultras and GTs, many of them has similar PCB layouts.
The measuring point is as shown and default is around 2.05v.
To measure the voltage, simply put red tip of multimeter to the point shown
and black tip to any ground.
Connect a 500K ohms VR across resistor as shown.
Original resistance of the resistor marked can be around 43k ohms to 30K ohms
depending on the cards. Set the 500K ohms variable resistor at maximum resistance
first and measure VDDR and reduce resistance to increase voltage. Take note
that a little adjustment can increase voltage quite a bit. So adjust carefully
This can be applied on a few of the AGP 6800 ultras and GTs, such as the Inno3D
ones. However, some cards such as the Asus 6800 Ultra PCI Express have different
For the Asus PCI Express 6800 Ultra, and perhaps some of the other cards out
there, Memory voltage can be modded this way.
The VDDR measure spot is as shown. Locate the resistor marked. Measure its
resistance across both ends of the resistor. Its is about 71.5K ohms on the
Asus card. Use a soldering iron to remove this resistor and replace it with
a 100K VR adjusted to whatever the original resistance is.
In this case, I adjusted the 100K VR to 71.5K ohms.
Turn on the PC to check that the VDDR is still near its original voltage. For
this mod, Increase resistance to increase voltage instead of
decreasing resistance. Take note that a little adjustment can increase voltage
quite a bit. So adjust carefully and slowly.
For the VGPU mod, you can refer to this article.